#include "index.hpp"
#include"util.hpp"
#include<algorithm>
#include<jsoncpp/json/json.h>

namespace ns_searcher
{
    struct InvertedElemPrint{
        uint64_t doc_id;
        int weight;
        std::vector<std::string> words;
        InvertedElemPrint():doc_id(0),weight(0){}
    };

    class Searcher
    {
    private:
        ns_index::Index *index; // 供系统进行查找的索引
    public:
        Searcher()
        {
        }
        ~Searcher() {}
    public:
        void InitSearcher(const std::string &input)
        {
            //1,获取或创建index对象
            index = ns_index::Index::GetInstance();
            std::cout << "获取index单例成功。。。" <<std::endl;
            //2，根据index对象建立索引结构
            index->BuildIndex(input);
            std::cout << "建立正派倒排索引成功" <<std::endl;

        }
        //query:搜索关键字
        //json：返回给用户浏览器的数据搜索结果
        void Search(const std::string &query,std::string *json_string)
        {
            //1，分词：对query进行按照searcher的要求进行分词
           std::vector<std::string> words;
           
            ns_util::JiebaUtil::CutString(query,&words);
           
            //2，触发：就是分局分词的各个“词”，进行index查找
           //ns_index::InvertedList inverted_list_all;
           std::vector<InvertedElemPrint> inverted_list_all;
           
           std::unordered_map<uint16_t,InvertedElemPrint> tokens_map;//查询文档去重

           
           
           for(std::string word : words)
            {
                boost::to_lower(word);
                ns_index::InvertedList *inverted_list = index->GetInvertedList(word);
                if(nullptr == inverted_list)
                {
                    continue;
                }
                //不完美的地方：
                //inverted_list_all.insert(inverted_list_all.end(),inverted_list->begin(),inverted_list->end());
                for(const auto &elem : *inverted_list){
                    auto &item = tokens_map[elem.doc_id];
                    //item一定是doc——id相同的print节点
                    item.doc_id = elem.doc_id; 
                    item.weight += elem.weight;
                    item.words.push_back(elem.word);
                }
          
            }
            for(const auto& item : tokens_map){
                inverted_list_all.push_back(std::move(item.second));
            }
            //3，合并排序：根据汇总查找结果，按照相关性降序排序
            std::sort(inverted_list_all.begin(),inverted_list_all.end(),[](const InvertedElemPrint & e1,const InvertedElemPrint &e2){
                return e1.weight > e2.weight;
            });

            //4，构建：根据查找出来的结果构建json串---jsoncpp
            Json::Value root;
            for(auto &item : inverted_list_all)
            {
                ns_index::DocInfo * doc = index->GetForwardIndex(item.doc_id);
                if(nullptr == doc) continue;
                Json::Value elem;
                elem["title"] = doc->title;
                elem["desc"] = GetDesc(doc->content, item.words[0]);//content是文档的去标签的结果
                elem["url"] = doc->url;

                //for test
                elem["id"] = (int)item.doc_id;
                elem["weight"] = item.weight;
                root.append(elem);
            }

            // Json::StyledWriter writer;
            // *json_string = writer.write(root);
          Json::FastWriter writer;
          *json_string = writer.write(root);



        }

        std::string GetDesc(const std::string &html_content,const std::string &word)
        {
            //找到word在html_content中首次出现，然后往前找50字节（如果没有就从begin开始），往后找100字节，截取出这部分内容
           
           const int prev_step = 50;
           const int next_step = 100;
            //1，找到首次出现
            // std::size_t pos = html_content.find(word);
            // if(pos == std::string::npos)
            // {
            //     return "None1";
            // }

            auto iter = search(html_content.begin(),html_content.end(),word.begin(),word.end(),[](int x,int y){
                return (std::tolower(x) == std::tolower(y));
            });
            if(iter == html_content.end()) return "None1";
            
           int  pos = std::distance(html_content.begin(),iter);
            //2，获取begin或end位置
            int start = 0;
            int end = html_content.size() - 1;
            //如果之前有50加字符，就更新开始位置
            if(pos > start + prev_step)
            {
                start = pos - prev_step;
            }
            if(pos < end - next_step)
            {
                end = pos + next_step;
            }

            //3，截取子串，return
            if(start >= end) return "None2";
            std::string desc = html_content.substr(start,end-start);
        
            desc += "...";
            return desc;
        }
    };
}